After complaints about Apple's delayed compliance with open source licensing requirements for WebKit began gaining traction, Apple released the iOS 4.3 WebKit source code on Monday.

Last week, Harald Welte of GPL Violations called out Apple for a delay in releasing the source code for WebKit in iOS 4.3. Welte's complaint was picked up by IT Worldon Monday in a report also highlighting the more than two month delay. Apple released iOS 4.3 in March and iOS 4.3.3 last week.

The Cupertino, Calif., iPhone maker is obligated to simultaneously release the binary and source code for WebKit because it uses code licensed under the Lesser GNU Public License.

"It cannot be a simple oversight, as multiple inquiries have been made to Apple by interested developers. However, the source code yet has to be released," wrote Welte.

As noted byTUAW, Apple released the code for the iOS 4.3.3 version of WebKit on its open source resource site late Monday.

Given the recent public calls for the release of the source code, the timing of the release prompted speculation that Apple had waited until developers complained before releasing the code. Some internet commenters have suggested that the iOS team's source code release policy is to do nothing until someone complains. Apple reportedly took six months to release open source portions of iOS 4.1, waiting until prominent jailbreakers Comex and Saurik complained about the company's non-compliance.

However, John Gruber of Daring Fireball speculated last week that the delay may have had "something to do with the introduction of the Nitro JavaScript engine for MobileSafari, and the security implications of granting MobileSafari  and only MobileSafari  an exception to the system-wide ban on marking memory pages as executable."

iOS 4.3 brought Apple's Nitro JavaScript engine over from Mac OS X, resulting in performance more than twice as fast as previous versions of Mobile Safari.

Apple's delays have prompted comparisons to Google's decision to temporarily close the Android 3.0 Honeycomb source code. In March, Google closed availability of the Honeycomb source code for "the foreseeable future" because the software wasn't ready for smartphones. Android chief Andy Rubin responded to criticism regarding the decision by promising that the code would be released once the Android team finished porting features from the tablet-specific release to smartphones.